Delayed Wound Healing: How Long Healing Should Take and Why It Slows

How long should a wound take to heal?

Healing time depends on how deep the wound is, where it is and how healthy you are. These are typical times for a healthy adult:

Strength keeps building for months after the surface has closed. A healed scar reaches only about 80% of normal skin strength.

Healing normally moves through four overlapping stages: bleeding stops (hemostasis), inflammation with mild redness and swelling for a few days, new tissue growth (pink, bumpy granulation tissue fills the wound), and remodeling, when the scar flattens and fades over a year or more. Delay usually happens when a wound gets stuck in the inflammation stage.

What slows wound healing

Factors in the wound itself

• Infection: bacteria prolong inflammation and break down new tissue. See wound infection for the signs.
• Pressure, friction or movement: a wound over a heel, sacrum or joint is repeatedly re-injured.
• Dead tissue or a foreign body: grit, splinters or stitches left in place block healing.
• Drying out: scabs and dry wounds heal more slowly than wounds kept moist under a dressing.
• Swelling: fluid in the tissue, especially in the lower legs, starves the wound of oxygen.

Health conditions

• Diabetes: high blood sugar impairs white blood cells and collagen formation, and neuropathy means injuries go unnoticed. Foot wounds are the biggest concern; see diabetic foot.
• Poor arterial blood flow: peripheral artery disease causes pale, painful wounds on the feet and toes.
• Poor vein return: venous insufficiency causes swollen legs and shallow wounds near the ankle.
• Anemia, kidney disease, liver disease and heart failure.
• Weakened immunity: HIV, cancer, chemotherapy.
• Obesity: fatty tissue has a poorer blood supply and wounds are under more tension.

Lifestyle, age and medicines

• Smoking: nicotine narrows blood vessels and carbon monoxide reduces oxygen delivery. Surgical wounds in smokers break down more often.
• Older age: skin is thinner and cells divide more slowly, so healing can take noticeably longer.
• Poor nutrition: low protein, vitamin C (severe deficiency causes scurvy), zinc and calories all slow repair. See malnutrition.
• Medicines: long-term steroids, some chemotherapy and immune-suppressing drugs, and radiation to the area.
• Alcohol misuse and poor sleep.

Signs a wound is healing too slowly

• It has not gotten smaller after 2 weeks
• The base stays yellow, gray or black rather than turning pink-red and granular
• Edges are rolled, thickened or undermined
• Drainage is increasing, cloudy or smelly (see wound drainage)
• Pain is getting worse rather than better
• The wound heals and then reopens

A wound that has not healed in 4 to 12 weeks is called chronic. The main types of non-healing wounds and specialist treatments are covered on our chronic wounds page.

How doctors find the cause

A clinician will look at the wound's size, depth, base and edges, and measure it to track progress. They will ask how it happened, what dressings you use and about diabetes, smoking and medicines. Tests may include:

• blood sugar and HbA1c
• blood count, kidney function, albumin and sometimes iron, vitamin and zinc levels
• foot pulses and an ankle-brachial index (ABI) to check circulation
• a wound swab only if infection is suspected, and an X-ray or MRI if bone infection is possible
• a biopsy of a wound that looks unusual or has not healed after months, to rule out skin cancer

How to help a slow wound heal

• Clean gently with tap water or saline. Avoid hydrogen peroxide, iodine or alcohol on open wounds, which damage healing cells.
• Keep it moist and covered with a dressing or petroleum jelly rather than letting a hard scab form.
• Take pressure off it: pressure-relieving cushions, changing position, or special footwear for foot wounds.
• Raise swollen legs above heart level when resting, and use compression only if a clinician has checked your arterial circulation.
• Control blood sugar if you have diabetes.
• Stop smoking, including vaping nicotine, ideally for several weeks before and after surgery.
• Eat enough protein and calories. Supplements help mainly if you are deficient.
• Do not pick scabs or soak a healing wound for long periods.

Specialist care may add debridement (removing dead tissue), advanced dressings, negative pressure wound therapy, treatment to restore blood flow, or antibiotics for confirmed infection.

Frequently asked questions

Why is my wound healing so slowly?

The most common reasons are infection, pressure or rubbing on the wound, poor circulation, diabetes, smoking, older age and poor nutrition. Steroids and other medicines can also slow repair. If a wound has not shrunk after 2 weeks, have a clinician look for the cause.

How long should a wound take to heal?

A minor cut or graze usually closes within 1 to 2 weeks. Stitched wounds close in 1 to 3 weeks depending on location. Deeper tissue keeps remodeling for months. A wound not healed by 4 to 6 weeks needs medical assessment.

Does diabetes cause delayed wound healing?

Yes. High blood sugar weakens the immune response and slows new tissue formation, and nerve damage and poor circulation add to the problem. Foot wounds in people with diabetes should be checked within a day or two, even if painless.

What speeds up wound healing?

Keeping the wound clean, moist and covered, relieving pressure, raising swollen legs, controlling blood sugar, stopping smoking and eating enough protein all help. Treating any infection or circulation problem is often what finally gets a stalled wound moving.

Is it better to let a wound breathe or cover it?

Covering is usually better. Wounds kept moist under a clean dressing heal faster, with less scarring, than wounds left to dry and scab. Change the dressing if it becomes wet or dirty.